Ringside Boxing Training Heavy Bag Heavy Duty Bag Spring (Up to 150 lbs.) This boxing heavy duty heavy bag spring can hold bags as heavy as 150 pounds Made of all steel construction this heavybag hanger spring is extra strong Spring will lesson the shock of hard hits, kicks and knees to preserve the longevity of your bag mounts Perfect for boxing, MMA, Muay Thai, or any of your favorite contact sport heavy bag training